Expose helper functions

[drohit-cb]

Description Of Change

As I work on enhancing our QuickStart guide to add a concrete example to do a e2e stake tx, I realized that having helper functions around reading unsigned txs given a workflow and then ability to sign unsigned txs given wallet's private key would be very helpful.

Testing Procedure

Created a demo app to import the newly exported functions and get a signed staking tx. This is the example that will go into our Quickstart guide.

import { StakingClient, TxSignerFactory, getUnsignedTx } from '@coinbase/staking-client-library-ts';

// Set your api key name and private key here. Get your keys from here: https://portal.cdp.coinbase.com/access/api
const apiKeyName: string = 'YOUR_API_KEY_NAME';
const apiPrivateKey: string = 'YOUR_API_PRIVATE_KEY';

// Set your wallet details
const walletAddress: string = 'YOUR_WALLET_ADDRESS';
const walletPrivateKey: string = 'YOUR_WALLET_PRIVATE_KEY';

const client = new StakingClient(apiKeyName, apiPrivateKey);

async function stake() {
    // Step 1 - Get an unsigned tx corresponding to a
    // stake of 11 wei ETH from your wallet on network Holesky.
    let workflow = await client.Ethereum.stake('holesky', walletAddress, '11');
    let unsignedTx = getUnsignedTx(workflow);
    console.log('Unsigned tx %s', unsignedTx);

    // Step 2 - Sign the unsigned tx with your wallet's private key.
    // Note: In production, this part would be performed via a wallet-sdk of your choice.
    const signer = TxSignerFactory.getSigner('ethereum');
    const signedTx = await signer.signTransaction(walletPrivateKey, unsignedTx);
    console.log('Signed tx %s', signedTx);

    console.log('You can use this UI https://holesky.etherscan.io/pushTx or ' +
    'APIs you are familiar with to help broadcast the signed tx on Holesky.');
}

stake().catch((error) => {
    console.error(error);
});